Classic UK Minitrix Models - Black 9F
I wasn't going to do this section.
Years ago, I took my damaged 9F apart, and it took me ages to put it
back together again. More recently, I had another go, but in the
meantime, various bits had gone missing. Last night, I wasn't happy
with the way it was running, so I took it all apart again, cleaned it
up, lubricated bits and put it all back together again. About 2 hours
in total - and that was taking pictures as well. It now runs more
smoothly than my newr 9Fs.
Easy when you know how. So here's how:
of the bits spread out. I didn't desolder the motor - you can see
these bits disconnected in the 'Motor' section. The eccentric valve
rod is broken off and missing on both sides of this loco. I've even
dismantled the tiny reduction gear and spindles from the motor
housing (2 tiny plastic cogs). Note the plastic pins from the centre
wheel which used to be attached to the eccentric valve gear.
photo from the right side showing the position of the reduction
gears and the locating spindles. The spindles are a tight push fit
into the chassis - but can be ejected with a firm push from a narrow
bladed screwdriver. It is useful to do this to be able to clean them
up, ensure that there is no damage to the teeth or hubs, regrease
them and replace them in better shape than they were. If removing the
motor, the black wire needs disconnected from the tender. (Cut it
inside the tender and resolder it later). The motor and the pickups
can be taken off in one piece by unscrewing the 2 motor screws (see
motor section) and unscrewing the single cheese head screw shown in
removing the motor, the black wire needs to be disconnected from the
tender. (Cut it inside the tender and resolder it later). The motor
and the pickups can be taken off in one piece by unscrewing the 2
motor screws (see motor section) and unscrewing the single cheese
head screw shown in the photo. Keep the wheels axles in pairs with
the coupling rods in place. The pair at the rear have tyres, the pair
at the front don't. The middle axle has a square hole in the wheel
for the crank rather than the round hole for the retaining pin, and
it has a larger plastic balance weight moulded into the spokes.
the reduction gearing. The pins help to keep things in approximately
the right place. The gearbox is quite wll protected, so I haven't
bothered too much about the surplus grease. When the axles are in
place, these stay firmly clamped in the frame, and the cogs spin on
the static axles.
better shot to show which gear goes where. The larger of the two has
just one cog and a larger hub on one side. The photo is taken looking
from the front of the loco.
shot taken from underneath the chassis before the cogs were firmly
located on pins or axles. Front is to the right of the photo. The
right side of the loco is at the top of the photo. Use long nosed
pliers to hold the axle by one end, and place it in the hole just
enough to hold it in position. With a light, look at the cog though
the axle hole from the other side. Use the pin to make sure that they
are aligned, and then firmly push the axle though.
the wheels and gears looks easy, but is quite tricky. Place all 4
gears into their (deeper) slots. Start with the rear set of wheels
(they have tyres). Remove the connecting rod from one side only -
prise the pins out by twisting a screwdriver between the wheel and
the coupling rod. (see photos in the Dismantle section of the
Mallard). Drop the first axle into place (check the spare end is
facing the middle axle position), and rotate the wheel so that the
crankpin hole is at the 12 o'clcok position. Easy. Now drop the 2nd
axle in. Then spend a bit of time ensuring that the hole is at 12
o'clock. As you do so, note that as you rotate the wheel, the plastic
cog will rise out of its slot, and the axles will rise out of theirs.
When you think you have them both correct, push the downwards on the
gears to make sure that they are seated, and check the positions again.
with two wheels and one red cog to keep in place, repeat the
operation for the middle axle.
with 3 axles and 4 cogs to hold, drop in the other pair of wheels
(Again easier if you remove the coupling rod from one side (the same
side as before !). Each time, ensure that the wheel is in its proper
position before moving to the next wheel. You have to do them in
sequence - rear to front or front to rear. Note that there is a
little play in each axle/cog. Make sure that all of the slack is
taken up in (say) the clockwise direction, before checking the
alignment. And keep checking that the axles and cogs are pushed down
fully into their slots.
may wish to place the bottom plate in position after fitting 3 axles
so that you can be sure that the rear 3 are definitely properly
located, before moving on to the front pair of axles. Removing the
bottom plate again without lifting the axles can be tricky though.
a final check that all 5 wheels are properly postioned, turn the
engine round and look at the other side. Whatever the position, the
spare end of the coupling rods should be hovering over the hole in
the centre wheel, and the coupling rods should form a straight line
across all 5 wheels. If not, something is mis-placed ! Ensure that
the alignment is not caused by some wheel being turned one way
against the free play while others are turned the other way.
don't forget to check that all of the axles and all of the cogs are
seated fully. Worth doing at this stage is to check that everything
runs smoothly by running a level surface or bit of track across the
wheels. Pressure on the wheels will keep the cogs in place. Fit the
bogie, making sure the chassis contact is properly positioned. Fit
the base plate - press down the centre and then work towards the
holes - and then try the run test with the loco the right way up. Try
it on the track too - but don't overdo the pressure which could
dislodge older, stretched rubber tyres. If all is Ok, refit the
coupling rods and pins, and try the test again.
refit the contact strip. The plastic base fits into two small
locating slots near the front. Make sure that all 6 contact points
sit on the flange edges before pressing it into place. They can slip
behind the wheels. Use tweezers to straighten the tabs which support
the contact strips if necessary - they should protrude horizontally
from the main copper strip. I'm not sure what the two tags near the
gearbox are for. When in position, screw down the circuit board - as
always, insert the screw in the board and offer both up to the
threaded hole. It saves trying to fiddle with big fingers and tiny
screws in tight places.
Maintaining Classic UK Minitrix Locos
The Minitrix trademark is currently owned by Märklin Inc.
Gebr. Märklin & Cie. GmbH, Stuttgarter Straβe 55-57, D-73033 Göppingen,